My invention pertains to apparatus for forming sheet metal ducts of variable configurations from pre-cut flat blanks.
Sheet metal fabrication requires the forming of ducts of a general conical configuration ranging from symmetrical cones to offset cones. In sheet metal shops this is performed by cutting a flat blank from the material to be formed by marking the material with a multiplicity of element lines of varying lengths which establishes the shape of the blank to be formed into the sheet metal duct.
Using conventional forming rolls of either the pinch or pyramid type the blank is fed through the rolls maintaining the element lines parallel to the feed rolls by continuous manual adjustment of the blank position. The axis of the bending roll is adjusted to a varying angle relative to the feed rolls to provide bending at the proper radius at the ends of each of the successive element lines.
Equipment is not available that will automatically maintain the element lines parallel to the feed rolls and simultaneously maintain adjustment of the bending roll axis relative to the feed rolls to form the blank into the desired duct. It is the general object of the present invention to provide apparatus for forming variable sheet metal configurations from a prepared blank without the necessity of continuous manual manipulation.
Another object of the invention is to provide apparatus that will automatically maintain the element lines parallel to the feed rolls as the successive element lines enter the feed rolls.
Another object of the invention is to provide apparatus that will automatically maintain adjustment of the bending roll relative to the feed rolls as the successive element lines come in contact with the feed rolls.
Another object of the invention is to provide apparatus that can be pre-programmed to form the prepared blank to the desired duct configuration.
Another object of the invention is to provide apparatus that will repeatedly process successive identical blanks to the desired configuration.
Another object of the invention is to provide apparatus that is capable of forming continuously variable conical sections.
Another object of the invention is to provide apparatus that will function without the need for continuous operator manipulation.
Another object of the invention is to provide apparatus that is adaptable to various thicknesses of blank material.
Broadly considered the foregoing and other objects of this invention are accomplished by apparatus which comprises power-driven feed rolls and pinch rolls adapted to pinch the material being formed into contact with the drive rolls. A bending roll is spaced from the drive rolls and pinch rolls with its axis parallel to the pinch rolls in one plane and adapted to have its axis positioned at an angle to the axis of the inch rolls in a plane 90.degree. to the first plane. The drive and pinch rolls are mounted on a frame in a manner providing for being shifted longitudinally relative to the length of the frame and bending roll. Sensing elements are positioned on the axis of the pinch roll to detect the position of the baseline and element lines on the blank being formed. The sensing elements direct the longitudinal position of the feed rolls and pinch rolls relative to the bending roll and direct the adjustment of the bending roll relative to the feed rolls and pinch rolls as the blank progresses between the pinch rolls and the feed rolls.